/Engine/Source/Runtime/GeometryCore/Public/Util/UniqueIndexSet.h
TODO: second bit set that tracks which blocks of ints have been set. This would allow for clears to be much quicker for subsets. (would want to profile to see that it helps, but the bit set is still 0.125mb per million indices, which isn't a trivial amount to set to zero...) TODO: alternately, use aTSetinstead of Bits array if we know that the number of values we are going to add is very small? This would avoid clears.
~FUniqueIndexSet()